JPH1181928A - Valve timing adjusting device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure the sealing property with chip seal by holding a seal member for sealing between a housing member and a vane rotor with a side clearance set within a specified range. SOLUTION: Vanes 1a-1c of a vane rotor l are formed into a sector form, and these vanes 1a-1c are housed freely to be turned in a sector space formed between shoes 2a-2c of a shoe housing 2 as a housing member. A slit-like groove 19 is provided in the vanes 1a-1c and a support member 1d of the vane rotor 1, and a chip seal 3 as a seal member is loosely fitted in the groove 19, and a side clearance 18 set at 100 μm-500 μm between a side surface of the chip seal 3 and the vane rotor 1 as a member for holding the chip seal 3. Sealing property by the chip seal 3 is thereby secured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter referred to as an "internal combustion engine").
The present invention relates to a valve timing adjusting device for changing the opening / closing timing of at least one of an intake valve and an exhaust valve of an “internal combustion engine” according to operating conditions.

[0002]

2. Description of the Related Art In a valve timing adjusting apparatus, in order to control a phase difference of a vane rotor with respect to a shoe housing with high accuracy, leakage of pressure oil from hydraulic chambers of an advance hydraulic chamber and a retard hydraulic chamber is reduced. There must be. As a technique for solving this problem, Japanese Patent Laid-Open No. 9-1122 is disclosed.
No. 23 is known. Here, a tip seal as a seal member is attached to the clearance between the inner peripheral wall of the shoe housing and the outer peripheral wall of the vane rotor to minimize the communication between the advance hydraulic chamber and the retard hydraulic chamber through the clearance. doing.

[0003]

However, in the prior art, there is no mention of an appropriate value of the side clearance between the vane rotor and the tip seal and the surface roughness of the sealing surface between the vane rotor and the tip seal. If the side clearance between the vane rotor and the tip seal is too narrow, sufficient pressure oil is not supplied to the back side of the tip seal and the side clearance, so the tip seal is not pressed against the inner peripheral surface of the housing and the side surface in the groove of the vane rotor by hydraulic pressure. Sealability is reduced. Conversely, if the clearance is too wide, the posture of the tip seal becomes unstable, and the sealing performance is reduced. In addition, when the surface of the seal surface between the housing member and the chip seal has a mirror finish, the seal surface is in close contact with the vane rotor and it is difficult to operate smoothly.

The present invention has been made in view of this problem, and has as its object to ensure the sealing performance of a tip seal. Further, it is another object of the present invention to prevent the tip seal from being in close contact with the sliding surface in sliding contact, and to smoothly operate the vane rotor. Therefore, an object of the present invention is to provide an appropriate value of the side clearance of the tip seal or an appropriate value of the surface roughness of the sealing surface of the tip seal or a member to which the tip seal slides.

[0005]

According to a first aspect of the present invention, there is provided a seal member which is held by one of a housing member and a vane rotor, makes sliding contact with the other, and seals between the housing member and the vane rotor. And using a technical means that the seal member is held with a side clearance of 100 μm or more and 500 μm or less.

[0006] When pressure oil is supplied to the advance hydraulic chamber or the retard hydraulic chamber, the pressure oil flows from the high pressure side to the low pressure side hydraulic chamber in such a way that the inner peripheral seal surface of the housing member and the outer peripheral wall of the vane rotor are in contact with each other. And transmitted to the side clearance of the seal member. The seal member is pressed against the other side (low pressure side) by the hydraulic pressure from the side clearance, and further pressed against the inner peripheral surface of the housing by the hydraulic pressure from the clearance behind the tip seal, so that the side surface of the seal member and the housing member or Sealing with the vane rotor can be reliably performed.

[0007] In the invention of claims 2 and 3,
As the sealing member, a technical means of making sliding contact with a sealing surface having a surface roughness of 1.6z or more is used alone or in combination with the above-mentioned configuration with the side clearance. When oil is press-fitted into the advance hydraulic chamber or the retard hydraulic chamber, a small amount of oil is also interposed on the seal surface with which the seal member slides. If both of the seal surfaces forming the sliding contact seal surface are mirror-finished, the two are in close contact with each other and the vane rotor becomes difficult to operate smoothly. When the surface roughness of any one of the sealing surfaces is 1.6z or more, the close contact between them is suppressed, and the operation of the vane rotor on the sealing surface becomes smooth.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve timing adjusting apparatus to which the present invention is applied will be described below with reference to FIGS. 1 to 3 as an embodiment of the present invention. FIG. 1 is a cross-sectional view showing a valve timing adjusting device according to the present invention. The shoe housing 2 has trapezoidal shoes 2a, 2b and 2c arranged at substantially equal angular intervals in the circumferential direction. Then, the shoes 2a, 2b, and 2c are
are connected by d. Shoes 2a, 2b and 2c
Are formed in an arc shape.
A fan-shaped space is formed between the shoes 2a, 2b, and 2c in the circumferential direction as accommodation rooms for the vanes 1a, 1b, and 1c, respectively.

The vane rotor 1 comprises a support member 1d, and vanes 1a, 1b and 1c which extend radially outward from the support member 1d at substantially equal angular intervals, are formed integrally with the support member 1d, and rotate together with the support member 1d. . Vane 1
a, 1b and 1c are formed in a fan shape.
a, 1b and 1c are rotatably accommodated in a fan-shaped space formed between the shoes 2a, 2b and 2c.

A retard hydraulic chamber 13 is formed between the shoe 2a and the vane 1a, a retard hydraulic chamber 14 is formed between the shoe 2b and the vane 1b, and the shoe 2c and the vane 1c are formed.
A retard hydraulic chamber 15 is formed between the two. An advanced hydraulic chamber 10 is formed between the shoe 2c and the vane 1a, and an advanced hydraulic chamber 1 is formed between the shoe 2a and the vane 1b.
1 is formed, and an advanced hydraulic chamber 12 is formed between the shoe 2b and the vane 1c.

Vane 1a, 1b, 1c and support member 1
A slit-shaped groove 19 is provided in d, into which the tip seal 3 as a sealing member is loosely fitted. As shown in FIG. 2, a side clearance 18 is provided between the side surface of the chip seal 3 and the vane rotor 1 as a member for holding the chip seal. This side clearance 18
Is set in the range of 100 μm or more and 500 μm or less.
As shown in FIG. 3, a leaf spring 5 is provided on the back surface of the tip seal 3, and the tip seal 3 is pressed against the inner peripheral sealing surface of the shoe housing 2 by the elastic force of the leaf spring 5. The inner peripheral sealing surface of the shoe housing 2 with which the chip seal 3 slides and the sealing surface of the groove 19 of the vane rotor 1 with the chip seal 3 (the side surface of the groove 19) are not mirror-finished, and are 1.6z. The surface roughness is as described above.

The valve timing adjusting device comprises a retard hydraulic chamber 1
The desired valve timing is obtained by adjusting the oil pressures of the hydraulic pressure chambers 3, 14, 15 and the advance hydraulic chambers 10, 11, 12 and controlling the phase difference of the vane rotor 1 with respect to the shoe housing 2. At the time of starting the engine, when the pressure oil from the oil pump (not shown) has not been introduced into any of the hydraulic chambers, the stopper pin is fitted into the stopper hole of the front plate (not shown), and the vane rotor 1 is moved by the stopper pin 9. , And the shoe housing 2. Advancing hydraulic chambers 10 and 1 from an oil pump through an oil passage 20
When the pressurized oil is supplied to the first and second stopper pins 9, the stopper pin 9 comes out of the stopper hole, and the vane rotor 1 and the shoe housing 2 are removed.
Is disconnected.

When pressure oil is fed from the oil pump to the retard hydraulic chambers 13, 14, 15 via the oil passage 21, the hydraulic oil is released from the advance hydraulic chambers 10, 11, 12 to an oil tank (not shown). You. Conversely, when pressure oil is pressure-fed from the oil pump to the advance hydraulic chambers 10, 11, 12 via the oil passage 20, the hydraulic oil is released from the retard hydraulic chambers 13, 14, 15 to the oil tank. There is a pressure difference between the hydraulic chamber on the side where the pressure oil is pumped and the hydraulic chamber on the side where it is released. The pressure oil in the high-pressure side hydraulic chamber is supplied to the shoe housing 2 in the direction of the low-pressure side hydraulic chamber.
Through the minute clearances 16 and 17 between the inner peripheral wall of the vane rotor 1 and the outer peripheral wall of the vane rotor 1 to reach the side clearance 18 between the tip seal 3 and the vane rotor 1. The tip seal 3 is actuated by hydraulic pressure from the side clearance 18.
It is pressed in the direction of the hydraulic chamber on the low pressure side of the vane rotor 1 and seals its contact surface. Furthermore, the tip spring 3 and the inner peripheral surface of the shoe housing 2 are pressed against the inner peripheral surface of the shoe housing 2 by being pressed against the inner peripheral surface of the shoe housing 2 by hydraulic pressure from the leaf spring 5 and the clearance behind the tip seal 3. The gap is sealed.

When oil is press-fitted into the advance hydraulic chamber or the retard hydraulic chamber, the tip seal 3 and the shoe housing 2
Although a small amount of oil is interposed between the tip seal 3 and the shoe housing 2, when both surfaces of the tip seal 3 and the shoe housing 2 are mirror-finished, the two adhere to each other and the vane rotor 1 becomes difficult to operate smoothly. Also, when the direction of rotation of the vane rotor 1 changes, the hydraulic chamber that was high in pressure before the change in the rotation direction becomes low in pressure, and the hydraulic chamber that was low in pressure becomes high in pressure. Therefore, the direction of the flow of the pressure oil that reaches the tip seal 3 through the minute clearances 16 and 17 is reversed. But,
If the side surface of the groove 19 facing the side clearance 18 and the side surface of the chip seal 3 are mirror-finished, the vane rotor 1 and the chip seal 3 are in close contact with each other and are difficult to separate.
The tip seal 3 is not pressed against the low pressure side surface of the groove 19 (after the rotation direction of the vane rotor 1 is changed). For this reason, side clearance occurs on the low pressure side of the groove 19, and the tip seal 3 becomes unstable.

The surfaces of the shoe housing 2 and the chip seal 3 that are in sliding contact with each other and the groove 19 that faces the side clearance 18 and the surface of the chip seal 3 have a roughness of 1.6z.
With the above, the vane rotor 1 operates smoothly without the sealing surfaces being in close contact as described above, and the tip seal 3 is also pressed down to the low pressure side of the groove 19. Thus, 100 μm is provided between the vane rotor 1 and the tip seal 3.
By providing the side clearance 18 of 500 μm or less, pressure oil is supplied to the side clearance 18 from the high pressure side hydraulic chamber, and the tip seal 3 is pressed in the direction of the low pressure side hydraulic chamber of the vane rotor 1. The tip seal 3 is pressed against the inner peripheral surface of the housing by the hydraulic pressure of the clearance at the rear surface of the housing, so that the contact surface can be sealed. This side clearance 18
If the width is too narrow, the pressure oil will not be supplied sufficiently and the sealing performance will decrease.If the width is too wide, the tip seal will become unstable and the sealing performance will deteriorate. There must be.

Further, the inner peripheral sealing surface of the shoe housing 2 which is in sliding contact with the tip seal 3 and the side surface of the groove 19 in the vane rotor 1 are not mirror-finished, and a surface roughness of 1.6z or more is provided. 3 can be prevented from sticking. About this surface roughness,
Instead of being provided on the inner peripheral sealing surface of the shoe housing 2 and the side surface of the groove 19, the shoe housing 2 of the tip seal 3 is used.
May be provided on the side of the chip seal 3 and the sealing surface that slides. In addition, the sealing surface and the side surface must have such a smooth surface that the sealing function is achieved. Further, the tip seal 3 may be held by the shoe housing 2.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a valve timing adjusting device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the vicinity of a tip seal 3 in FIG.

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 vane rotor 1a, 1b, 1c vane 1d support member 2 shoe housing 2a, 2b, 2c shoe 2d peripheral wall 3 chip seal 9 stopper pin 10, 11, 12 advanced hydraulic chamber 13, 14, 15 retarded hydraulic chamber 16, 17 clearance 20, 21 oilway

Claims (3)

[Claims] 1. A valve timing adjusting device for an internal combustion engine provided in a driving force transmission system for transmitting a driving force from a driving shaft of the internal combustion engine to a driven shaft for opening and closing at least one of an intake valve and an exhaust valve of the internal combustion engine. A housing member, a vane rotor housed in the housing member and having a vane rotatable relative to the housing member only within a predetermined angle range, and a vane rotor held by one of the housing member and the vane rotor, and A valve member for slidingly contacting and sealing between the housing member and the vane rotor, wherein the seal member is held with a side clearance of not less than 100 μm and not more than 500 μm. Adjustment device. 2. The valve timing adjusting device for an internal combustion engine according to claim 1, wherein the sealing member is in sliding contact with a sealing surface having a surface roughness of 1.6z or more. 3. A valve timing adjusting device for an internal combustion engine provided in a driving force transmission system for transmitting a driving force from a driving shaft of the internal combustion engine to a driven shaft that opens and closes at least one of an intake valve and an exhaust valve of the internal combustion engine. A housing member, a vane rotor housed in the housing member and having a vane rotatable relative to the housing member only within a predetermined angle range, and a vane rotor held by one of the housing member and the vane rotor, and A seal member that is in sliding contact and seals between the housing member and the vane rotor, wherein the seal member is in sliding contact with a seal surface having a surface roughness of 1.6z or more. Valve timing adjustment device.